Method for obtaining thin, light and rigid metal parts

Abstract

The invention concerns a method for producing parts made of thin, light and rigid metal alloy essentially having the following steps: producing a core having the part shape; producing cavities in the core; producing shells made of metal alloy combined with reinforcing fibers with high modulus of elasticity; densifying the shells; and diffusion welding of the shells on the core by compression at temperature and pressure conditions for isothermal forging of the metal alloy used.

What is claimed is:  
     
       1. Process for obtaining thin, lightweight and rigid metal parts, said process comprising the following steps: 
       producing a thin core made of a metal alloy;  
       applying, to each face of the core, a shell consisting of reinforcing fibers having an elastic modulus at least equal to four times that of the metal alloy, said reinforcing fibers being embedded in a matrix made of a matrix-forming metal alloy;  
       densifying the shells by pressing at least in the thickness direction at a superplasticity temperature of the metal alloy of the matrix; and  
       diffusion-bonding of said shells to said core by pressing in the thickness direction of the part at an isothermal forging temperature of the metal alloy of the core and of the matrix of the shells;  
       wherein a plurality of cavities is produced in the core and emerge at least on one face of the core; and  
       wherein the shells are densified to the shape of the core.  
     
     
       2. Process according to  claim 1 , wherein a metal alloy, selected from a group consisting of titanium-, magnesium- and aluminum-based alloys, is employed; and wherein the reinforcing fibers, selected from a group consisting of silicon carbide, boron and carbon, are employed, so as to combine a light metal alloy with reinforcing fibers having a high strength and a high elastic modulus. 
     
     
       3. Process according to  claim 1  or  2 , wherein the diffusion-bonding step is carried out by pressing in a die in a press. 
     
     
       4. Process according to  claim 1  or  2 , wherein the diffusion-bonding step is carried out by isostatic pressing in an autoclave. 
     
     
       5. Process according to  claim 1  or  2 , wherein a volume fraction of the core is increased in fastening regions of the part so as to increase compressive strength of the part in the fastening regions. 
     
     
       6. Process according to  claim 5 , wherein the core is produced to extend into a blade and into a root of the part and wherein the cavities are produced in the core of the blade with a reduced volume fraction of the core, said part being a turbomachine blade assembly. 
     
     
       7. Process according to  claim 6 , wherein the blade assembly is made in a die. 
     
     
       8. Process according to  claim 1  or  2 , wherein the cavities are produced in the core along lines so as to form ducts between the shells. 
     
     
       9. Process according to  claim 8 , wherein the cavities each emerge only on one side of the core, so as to maintain cohesion of said core during production of the part.